Process for the semi-continuous dyeing of synthetic textile articles

ABSTRACT

Process for the semi-continuous dyeing of flat structures made from high-quality synthetic fibres, wherein the textile material that has been padded or printed with a dyestuff and an adjuvant is wound up on a perforated cylinder and this cylinder loaded with the goods is placed in the form of a skein into a pressure vessel, in which the pressure is greatly reduced and the padded or printed material is treated with a superheated liquid fixing medium and finished in usual manner.

United States Patent 11 1 von der Elitz Aug. 12, 1975 PROCESS FOR THE SEMI-CONTINUOUS DYEING OF SYNTHETIC TEXTILE ARTICLES [75] Inventor: Hans-Ulrich von der Elitz, Frankfurt am Main, Germany [73] Assignee: Hoechst Aktiengesellschaft,

Frankfurt am Main, Germany [22] Filed: Mar. 26, 1973 [2l] Appl. No.: 344,968

[30] Foreign Application Priority Data Mar. 29, 1972 Germany 2215297 [52] US. Cl. 8/174; 8/149.3; 8/158 [51] D06P 5/00 [58] Field of Search 8/149.3, 158, 174

[56] References Cited UNITED STATES PATENTS 2,235,165 3/1941 Platt 8/l49.3

2,446,502 8/1948 Wehrli 8/149.3 2,468,081 4/1949 Koster 8/l49.3 2,936,212 5/1960 Karrer 8/158 3,730,678 5/1973 Wedler et al. 8/149.3

Primary ExaminerBenjamin R. Padgett Assistant Examiner-B. Hunt Attorney, Agent, or Firm-Curtis, Morris & Safford 57 I ABSTRACT 3 Claims, N0 Drawings PROCESS FOR THE SEMI-CONTINUOUS DYEING OF SYNTHETIC TEXTILE ARTICLES The present invention relates to an improved process for the semi-continuous dyeing of flat structures made from high-quality synthetic fibers.

Special care is required for the treatment of textile material made from texturized polyester fibers, especially of structured knit fabrics, in order to preserve the valuable properties, such as elasticity in each direction, soft feel and fullness of the goods. For a fiber that has been thermally texturized may lose texturization owing to thermal overstrain, the more so if, in addition to thermal overstrain, the fiber has to stand mechanical overstrain by being pulled or pressed too hard.

It is known that knit fabrics, preferably manufactured from texturized polyester fibers, can be dyed with disperse dyestuffs in closed systems from aqueous liquors at elevated temperature, for example at 120 130C, under static pressure. Depending on the apparatus used, the material is dyed in open width or in the form of hanks. Both methods have in common to require a relatively long time for dyeing in order to afford a good color yield. levelness and dye penetration. When dyeing the material in open width, this operation is performed on a beam. For this purpose, the goods are wound up on a perforated cloth beam and penetrated first by a cold dyeing liquor and then by a dyeliquor that has been heated to dyeing temperature. In doing so, the mutual pressure of the layers of the wound-up goods and the thermal influences cause an undesired and often unacceptable flattening of the goods, especially on the structured surface of the goods. This disadvantage can be avoided by dyeing on special apparatuses. but their capacity is limited and the lots obtained from a dyeing charge are therefore relatively small. Expensive compound machines allow the individual charge to be increased but the time required for dyeing is as long as before. In addition, according to all those methods, faulty levelness of the dyeing can often be avoided or reduced by adding adjuvants but only to such an extent that useful goods are still obtained, since the dispersed dyestuff has to be pumped together with the liquor through the material.

It is, furthermore, known that flat structures made from texturized polyester fibers can be dyed with Anthrasol dyestuffs (leuco esters of vat dyes) under certain conditions according to a modified Thermosol process. In general, however. the Thermosol dyeing method does not play an important part in the production of medium and deep shades on texturized material webs, in spite of its simple and advantageous dyeing technique. With dyeings produced by the Thermosol process. it has not yet been possible to avoid or at least reduce the harsh feel, the less bulky. meagre goods and the unlevel dye penetration in the case of highquality knit fabrics made from texturized polyester fibers.

To overcome those difficulties. attempts have been made to produce better dyeings according to the padpressure steaming process. Although the feel of the goods is improved in this case, an unlevel aspect and a certain cracking" effect on the material prove that the padding and subsequent steam fixation under pressure neither yield optimum results. By the terms cracking or cracked fabrics in the case of elastic goods mostly knit fabrics there are to be understood light spots which become visible in the interior of the knit goods upon stretching the material in transverse direction.

It has now been found that the above-cited disadvantages and difficulties can be overcome by winding up the material that has been padded or printed with a dyestuff and an adjuvant, without intermediate drying, onto a perforated cylinder, placing the cylinder loaded with the goods in the form of a skein into a pressure vessel, evacuating the vessel and treating the material with a superheated liquid fixing medium.

The pressure in the vessel is generally reduced to about 10 mm of mercury or less but it may also be atmospheric pressure. In this case, the extraordinarily short reaction time is increased to only a slight extent.

After the vessel has been evacuated, the fixing medium that has been prepared in a pressurized container, preferably water of to 135C, in particular of C, is introduced, optionally via a pressurereducing valve, into the pressure vessel so as first to penetrate the goods on the perforated cylinder in such a manner that it enters the vessel through the goods from the interior of the cylinder. In special cases, the liquor may be allowed to enter the cylinder through the goods, coming from the vessel. To prolong the period of treatment, the liquor that has entered the evacuated vessel and which may also contain dyestuffs and/or adjuvants, can be pumped back again, thus causing it to circulate through the goods several times.

When prints are fixed according to this process, it is advantageous to dry them intermediately. To prevent staining, a thin fabric, for example a cotton (calico) cloth, is advantageously wound up together with the printed material so as to protect the prints.

Instead of water, azeotropic mixtures with organic solvents, or organic solvents alone may also be used as fixing media, the temperatures being adjusted accordingly.

Surprisingly, while penetrating the goods the fixing medium brings about a very rapid fixation of the dyestuff applied by padding and prevents the dyestuff from migrating to an undesired extent as well as from being dissolved off and thus giving shade differences at the ends (tailing) and sides (edge-to-edge shading) of the fabric. However, migration of the dyestuff is not impeded entirely so that levelness and dye penetration of the fabrics are substantially better than those obtained according to conventional continuous methods. There is no flattening nor harsh feel of the knit fabrics. As compared to the known high-temperature exhaust pro cess, the period required for the treatment is substantially shortened. According to the process of the invention, the total time required for the dyeing operation is also shortened and the amount of water spent is reduced, since the aqueous fixing liquor can be used several times, where required via an adsorption column and regeneration. The fixing liquors are contaminated but a little and therefore pose hardly any sewage water problems. Moreover. the process of the invention permits rationalizing the dyeing operation by fixing the first padded lot at the same time as the following lot is padded and wound up.

The following examples illustrate the invention. the parts and percentages being by weight unless stated otherwise.

EXAMPLE 1 A stretch knit fabric made of texturized polyester fibers was padded via a broad-stretching device at room temperature and with a liquor pick-up of 70 percent in an aqueous liquor containing, per liter,

20 g of a red disperse dyestuff of the formula The pl-l-value of the liquor was adjusted to 5 by means of acetic acid.

After padding, the goods were wound up loosely on a perforated cylinder, without intermediate drying, and the cylinder was placed into a pressure vessel. After the vessel had been closed, the pressure was greatly reduced. As a fixing liquor, water of 130C, which had been prepared separately in a pressurized container, was allowed to enter the vessel so as first to penetrate the wound-up goods. After the treatment vessel had been filled, the liquor was pumped back into the container, and the pressure in the vessel was allowed to come to normal. The goods were then withdrawn and rinsed with warm and cold water.

A red dyeing was obtained having very good levelness and dye penetration even inside the stretch knit fabric. The feel and structure of the goods were not deteriorated.

EXAMPLE 2 Piece-goods made from texturized polyester fibers having anelastic crepe structure were padded at room temperature and with a liquor pick-up of 70 percent in an aqueous liquor containing, per liter,

30 g of a golden-yellow disperse dyestuff of the formula g ofa non-ionic thickener on the basis of fully etherified (methylated) locust bean flour,

7 g of a non-ionic wetting agent (isotridecanol with 5 mols of ethylene oxide), and

5 g of a non-ionic emulsifier (castor oil with 36 mols of ethylene oxide).

The pH of the liquor was adjusted to 5 by means of acetic acid. After padding, the material was wound up loosely on a perforated cylinder, without intermediate drying, and the cylinder was placed in a pressure vessel which was closed. Pressure in the vessel was then greatly reduced and water of 130C was introduced, as a fixing liquor prepared in a separate pressurized container, into the pressure vessel so as first to penetrate the wound-up goods. The fixing liquor was forced to circulate in the indicated direction for a short time (1 to 2 minutes) and then pumped back into the container. After equalization of pressure the dyed goods were withdrawn and rinsed with warm and cold water.

A bright level golden-yellow dyeing was obtained. The structure of the knit fabric and the feel of the goods were not deteriorated.

EXAMPLE 3 10 g of the dyestuff of the formula and 5 g of the dyestuff of the formula N11 O OH n I II I 011 N H were first pasted up with g of cold water, and the paste was then dispersed with 300 g of boiling water. This dispersion was then stirred through a fine-meshed sieve into 600 g of a thickening consisting of a mixture of 300 g of crystal gum (25 and a 12 percent aqueous solution of the addition product of 2000 mols of ethylene oxide on 1 mol of stearic acid.

The printing paste thus obtained was printed on a knit fabric made from texturized polyester fibers, and the fabric was dried.

The dried goods were then wound up on a perforated cylinder and placed in a pressure vessel which was closed. As a fixing medium which had been prepared in a separate pressurized container, water of C was fed in the treatment vessel as quickly as possible so as first to penetrate the goods wound up on the cylinder. After the vessel had been filled and the fixing liquor allowed to act on the goods for a short time, while circulating by means of a pump, the fixing liquor was pumped back into the container, pressure was released, and the goods were withdrawn and rinsed with warm and cold water.

A green print was obtained with the feel and structure unaffected.

I claim:

l.-ln a process for. thesemi-continuous fixation of heat-fixable dyestuffs upon flat structures made from texturized polyester fibers, wherein a textile material that has been padded or printed with a dyestuff and an adjuvant is wound up on a perforated cylinder and said cylinder loaded with the textile material is placed in the form of a skein into a pressure vessel, the improvement which comprises: reducing the pressure in said pressure vessel to less than atmospheric pressure; introducing into said pressure vessel liquid water at a temperature of 110 to 135C, substantially free of dyestuffs and other adjuvants; and permitting the heated water to act upon the dyestuffs padded or printed upon the textile material, thereby exploiting the pressure difference between the water introduced into and the textile material in the pressure vessel.

2. A process as recited in claim 1 wherein the said pressure vessel is evacuated to a pressure of mm of mercury or less.

3. In a process for the semi-continuous fixation of heat-fixable dyestufis upon flat structures made from texturized polyester fibers, wherein a textile material that has been padded or printed with a dyestuff and an adjuvant is wound up on a perforated cylinder and said cylinder loaded with the textile material is placed in the form of a skein into a pressure vessel, the improvement which comprises: introducing liquid water under superatmospheric pressure and at a temperature of 1 10 to C to said pressure vessel, the interior of which is under normal atmospheric pressure.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 1 3,899,291

DATED August 12, 1975 INVENTOR(S) Hans-Ulrich Von der Eltz It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Signed and Scaled this seventh Day of 0mm1975 [SEAL] AlteSl.

RUTH C. MASON C. MARSHALL DANN Alleslmg Ojjrcer (ommissimwr uj'larents and Trademarks In Item [75] of the Heading, correct "Elitz" to read Eltz 

1. IN A PROCESS FOR THE SEMI-CONTINOUS FIXATION OF HEAT-FIXABLE DYESTUFFS UPON FLAT STRUCTURES MADE FROM TEXTURIZED POLYESTER FIBERS, WHEREIN A TEXTILE MATERIAL THAT HAS BEEN PADDED OR PRINTED WITH A DYESTUFF AND AN ADJUVANT IS WOUND UP ON A PERFORATED CYLINDER AND SAID CYLINDER LOADED WITH THE TEXTILE MATERIAL IS PLACED IN THE FORM OF A SKIN INTO A PRESSUE VESSEL, THE IMPROVEMENT WHICH COMPRISES: REDUCING THE PRESSURE IN SAID PRESSURE VESSEL TO LESS THAN ATMOSPHERIC PRESSURE, INTRODUCING INTO SAID PRESSURE VESSEL LIQUID WATER AT A TEMPERATURE OF 110* TO 135*C, SUBSTANTIALLY FREE OF DYESTUFFS AND OTHER ADJUVANTS, AND PERMITTING THE HEATED WATER TO ACT UPON THE DYESTUFFS PADDED OR PRINTED UPON THE TEXTILE MATERIAL, THEREBY EXPLOITING THE PRESSURE DIFFERENCE BETWEEN THE WATR INTRODUED INTO AND THE TEXTILE MATERIAL IN THE PRESSURE ESSEL.
 2. A process as recited in claim 1 wherein the said pressure vessel is evacuated to a pressure of 10 mm of mercury or less.
 3. IN A PROCESS FOR THE SEMI-CONTINOUS FIXATION OF HEAT-FIXABLE DYESTUFFS UPON FLAT STRUCTURES MADE FROM TEXTURIZED POLYESTER FIBERS, WHEREIN A TEXTILE MATERIAL THAT HAS BEEN PADDED OR PRINTED WITH A DYESTUFF AND AN ADJUVANT IS WOUND UP ON A PERFORATED CYLINDER AND SAID CYLINDER LOADED WITH THE TEXTILE MATERIAL IS PLACED IN THE FORM OF A SKEIN INTO A PRESSURE VESSEL, THE IMPROVEMENT WHICH COMPRISES: INTRODUCING LIQUID WATER UNDER SUPERATMOSPHERIC PRESSURE AND AT A TEMPERATURE OF 110* TO 135*C TO SAID PRESSURE VESSEL, THE INTERIOR OF WHICH IS UNDER NORMAL ATMOSPHERIC PRESSURE. 